Sensor system

ABSTRACT

A sensor system includes first sensor electrode groups and a first integrated circuit, and second sensor electrode groups and a second integrated circuit. The first integrated circuit and the second integrated circuit are controlled such that a first uplink signal, which is transmitted from the first integrated circuit via the first sensor electrode groups, and a second uplink signal, which is transmitted from the second integrated circuit via the second sensor electrode groups, are not transmitted at the same time.

BACKGROUND Technical Field

The present invention relates to a sensor system, and in particular, toa sensor system for a dual-screen model.

Description of the Related Art

In recent years, electronic devices of a type having two screens havebeen developed. This type of electronic device will be hereinafterreferred to as a “dual-screen model.” Along with the development of thedual-screen model, a technology has been developed for enabling input bya stylus (hereinafter referred to as “pen input”) and input by a finger(hereinafter referred to as “touch input”) on each of the two screens.

Patent Document 1 discloses an example of such a technology. Asdescribed in Patent Document 1, a dual-screen model includes a sensorsystem that includes an integrated circuit and a sensor electrode groupfor a first screen, an integrated circuit and a sensor electrode groupfor a second screen, and a host processor connected to each integratedcircuit. The sensor system realizes the pen input and the touch input.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: Japanese Patent Laid-Open No. 2019-133487

BRIEF SUMMARY Technical Problems

Some styluses are configured to receive an uplink signal transmittedfrom a screen and operate according to the received uplink signal. Inorder to enable the use of this type of stylus with a dual-screen model,it is necessary to prevent interference between uplink signalstransmitted from the two screens, respectively.

Therefore, one aspect of the present invention is to provide a sensorsystem that can prevent interference between the uplink signalsrespectively transmitted from the two screens disposed in thedual-screen model.

Further, when pen input is used in the dual-screen model, it ispreferable that a stylus that has started to be used on one screen cancontinuously be used on the other screen to which the pen tip is moved.

Therefore, another aspect of the present disclosure is to provide asensor system that enables continuous use of the stylus across the twoscreens included in the dual-screen model.

Further, when touch input is used in the dual-screen model, if a usertouches both of the two screens at the same time, there is a possibilitythat a finger touch detection signal that is being transmitted from oneintegrated circuit is received by the other integrated circuit. Suchreception needs to be avoided because this causes malfunction of theintegrated circuit and a host processor.

Therefore, yet another aspect of the present disclosure is to provide asensor system that can prevent the finger touch detection signal that isbeing transmitted from one integrated circuit from being received by theother integrated circuit.

Further, conventionally, two integrated circuits in a dual-screen modelhave operated without being synchronized with each other. Therefore,there have been cases where a host processor incorrectly processes asequence of position data supplied from each integrated circuit, as aresult of which drawing results are affected.

Therefore, still another aspect of the present disclosure is to providea sensor system in which the host processor can correctly process thesequence of the position data supplied from each integrated circuit.

Technical Solution

A sensor system according to a first aspect of the present disclosureincludes a first sensor electrode group and a first integrated circuitconnected to the first sensor electrode group, and a second sensorelectrode group and a second integrated circuit connected to the secondsensor electrode group. The first and second integrated circuits arecontrolled such that a first uplink signal that is transmitted from thefirst integrated circuit via the first sensor electrode group and asecond uplink signal that is transmitted from the second integratedcircuit via the second sensor electrode group are not transmitted at thesame time.

A sensor system according to a second aspect of the present disclosureincludes a first sensor electrode group and a first integrated circuitconnected to the first sensor electrode group, and a second sensorelectrode group and a second integrated circuit connected to the secondsensor electrode group. When the first integrated circuit is paired witha stylus, the first integrated circuit shares pairing informationregarding the pairing, with the second integrated circuit.

A sensor system according to a third aspect of the present disclosureincludes a first sensor electrode group and a first integrated circuitconnected to the first sensor electrode group, and a second sensorelectrode group and a second integrated circuit connected to the secondsensor electrode group. While one of the first and second integratedcircuits is performing a touch input detection operation, the other oneof the first and second integrated circuits is restricted fromperforming the touch input detection operation.

A sensor system according to a fourth aspect of the present disclosureincludes a first sensor electrode group and a second sensor electrodegroup, a first integrated circuit configured to perform a touch inputdetection operation by supplying a first finger touch detection signalto the first sensor electrode group, and a second integrated circuitconfigured to perform the touch input detection operation by supplying asecond finger touch detection signal to the second sensor electrodegroup. The first and second finger touch detection signals are pulsesignals configured such that temporal positions of edges of theirrespective pulse sections are different from each other.

A sensor system according to a fifth aspect of the present disclosureincludes a first sensor electrode group and a first integrated circuitconnected to the first sensor electrode group, and a second sensorelectrode group and a second integrated circuit connected to the secondsensor electrode group. The first and second integrated circuits eachperform a touch input detection operation in synchronization with eachother.

Advantageous Effects

According to the first aspect of the present disclosure, the first andsecond uplink signals are not transmitted at the same time. Therefore,it is possible to prevent interference between the uplink signalstransmitted from two screens disposed in a dual-screen model.

According to the second aspect of the present disclosure, the pairinginformation is shared between the first and second integrated circuits.This enables continuous use of the stylus across the two screensincluded in the dual-screen model.

According to the third aspect of the present disclosure, while oneintegrated circuit is performing the touch input detection operation,the other integrated circuit is restricted from performing the touchinput detection operation. Therefore, it is possible to prevent thefinger touch detection signal that is being transmitted from oneintegrated circuit from being received by the other integrated circuit.

According to the fourth aspect of the present disclosure, the temporalpositions of the edges of their respective pulse sections are differentfrom each other between the first finger touch detection signal and thesecond finger touch detection signal. Therefore, it is possible toprevent the finger touch detection signal that is being transmitted fromone integrated circuit from being received by the other integratedcircuit.

According to the fifth aspect of the present disclosure, the first andsecond integrated circuits each perform the touch input detectionoperation in synchronization with each other. Therefore, a hostprocessor can correctly process the sequence of position data suppliedfrom each integrated circuit.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an external appearance of an electronicdevice 1 according to a first embodiment of the present disclosure.

FIG. 2 is a diagram illustrating a configuration of a sensor system 3,which is included in the electronic device 1.

FIG. 3 is a timing diagram illustrating an overview of operations of afirst integrated circuit 13 and a second integrated circuit 23.

FIG. 4 is a diagram illustrating a principle of a touch detectionoperation TD.

FIGS. 5A and 5B are diagrams each illustrating an example of specificwaveforms of signals s₁ to s_(K) that constitute a finger touchdetection signal FDS.

FIG. 6 is a timing diagram of signals transmitted and received by eachof the first integrated circuit 13, the second integrated circuit 23,and a stylus P.

FIG. 7 is a diagram illustrating a state in which a user is sliding afinger F on a first panel surface 11 with a hand H resting on a secondpanel surface 21.

FIG. 8 is a diagram illustrating an example of restriction of the touchdetection operation TD.

FIGS. 9A and 9B are diagrams each illustrating waveforms of the fingertouch detection signal FDS according to a second embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail belowwith reference to the drawings.

FIG. 1 is a diagram illustrating an external appearance of an electronicdevice 1 according to a first embodiment of the present disclosure. Astylus P and a finger F to be detected by the electronic device 1 arealso illustrated in this figure. FIG. 2 is a diagram illustrating aconfiguration of a sensor system 3, which is disposed in the electronicdevice 1 to detect the stylus P and the finger F.

As illustrated in FIG. 1 , the electronic device 1 includes a firsthousing 10 and a second housing 20, which are connected to each other bya connecting portion 2. The connecting portion 2 includes a hinge and aflexible substrate. The first housing 10 is configured to be rotatablethrough 360° around the connecting portion 2 as denoted by anillustrated dashed arrow A. The flexible substrate is a substrateconfigured to deform at an angle corresponding to relative positions ofthe first housing 10 and the second housing 20. In the flexiblesubstrate, wires are arranged for connecting between wires in the firsthousing 10 and wires in the second housing 20.

The first housing 10 has a first panel surface 11, and the secondhousing 20 has a second panel surface 21. The surface of each of thefirst panel surface 11 and the second panel surface 21 is flat. A usercan slide a pen tip of the stylus P and the finger F on the surfaces ofthe first panel surface 11 and the second panel surface 21. Further, thefirst panel surface 11 and the second panel surface 21 are each disposedon a surface of the corresponding housing such that the first panelsurface 11 and the second panel surface 21 face the same direction whenthe first housing 10 is set at a 180° position. Both the first panelsurface 11 and the second panel surface 21 have a rectangular shape andare disposed such that their respective long-side directions areperpendicular to a direction in which the first panel surface 11 and thesecond panel surface 21 are aligned when the first housing 10 is set atthe 180° position.

Here, each of the first panel surface 11 and the second panel surface 21may or may not serve as a display surface for display. As specificsystems to make each of the first panel surface 11 and the second panelsurface 21 function as the display surface of the display, an in-cellsystem, an on-cell system, an out-cell system, or any other varioussystems can be employed. In the case of the in-cell system, part ofelectrodes for driving pixels in the display (e.g., common electrodes ofa liquid-crystal display) function as part of sensor electrode groups tobe described later (e.g., a plurality of sensor electrodes 12 x or aplurality of sensor electrodes 22 x to be described later). In the caseof the on-cell system, although the sensor electrode groups to bedescribed later are disposed in the display, the sensor electrode groupsare disposed separately from the electrodes for driving the pixels inthe display. In the case of the out-cell system, the sensor electrodegroups to be described later are disposed on a display panel. In caseswhere both the first panel surface 11 and the second panel surface 21serve as the display surfaces of the displays, the electronic device 1functions as the dual-screen model described above.

Referring now to FIG. 2 , the sensor system 3 includes first sensorelectrode groups 12 x and 12 y, a first integrated circuit 13, firstlead-out wires (lines/traces) 14 x and 14 y, second sensor electrodegroups 22 x and 22 y, a second integrated circuit 23, second lead-outwires (lines/traces) 24 x and 24 y, and a host processor 30. Of these,the first sensor electrode groups 12 x and 12 y, the first integratedcircuit 13, and the first lead-out wires 14 x and 14 y are disposed inthe first housing 10, while the second sensor electrode groups 22 x and22 y, the second integrated circuit 23, the second lead-out wires 24 xand 24 y, and the host processor 30 are disposed in the second housing20. It is noted that, although the host processor 30 is disposed in thesecond housing 20, this arrangement is a mere example and the hostprocessor 30 may be disposed in the first housing 10.

As illustrated in FIG. 2 , the first integrated circuit 13 and thesecond integrated circuit 23 are connected to each other via a wire(line/trace) 31. Further, the first integrated circuit 13 and the secondintegrated circuit 23 are connected to the host processor 30 via wires(lines/traces) 32 and 33, respectively. Part of the wires 31 and 32extend into the above-described flexible substrate. It is noted that,although each of the wires 31 to 33 is depicted by a single line in FIG.2 , each of the wires 31 to 33 is a set of multiple wires in actualimplementation.

The first sensor electrode groups 12 x and 12 y are disposed inside thefirst panel surface 11 as also illustrated in FIG. 1 . Similarly, thesecond sensor electrode groups 22 x and 22 y are disposed inside thesecond panel surface 21. The first sensor electrode groups 12 x and 12 yrespectively include the plurality of sensor electrodes 12 x and aplurality of sensor electrodes 12 y. The plurality of sensor electrodes12 x, each of which extends along a long-side direction of the firstpanel surface 11, are arranged at equal intervals along a short-sidedirection of the first panel surface 11. The plurality of sensorelectrodes 12 y, each of which extends along the short-side direction ofthe first panel surface 11, are arranged at equal intervals along thelong-side direction of the first panel surface 11. Further, the secondsensor electrode groups 22 x and 22 y respectively include the pluralityof sensor electrodes 22 x and a plurality of sensor electrodes 22 y. Theplurality of sensor electrodes 22 x, each of which extends along along-side direction of the second panel surface 21, are arranged atequal intervals along a short-side direction of the second panel surface21. The plurality of sensor electrodes 22 y, each of which extends alongthe short-side direction of the second panel surface 21, are arranged atequal intervals along the long-side direction of the second panelsurface 21.

The first integrated circuit 13 is connected to each sensor electrode 12x via the corresponding one of the first lead-out wires 14 x. The firstlead-out wires 14 x are arranged so as to correspond one-to-one to thesensor electrodes 12 x. The first integrated circuit 13 is alsoconnected to each sensor electrode 12 y via the corresponding one of thefirst lead-out wires 14 y. The first lead-out wires 14 y are arranged soas to correspond one-to-one to the sensor electrodes 12 y. Similarly,the second integrated circuit 23 is connected to each sensor electrode22 x via the corresponding one of the second lead-out wires 24 x. Thesecond lead-out wires 24 x are arranged so as to correspond one-to-oneto the sensor electrodes 22 x. The second integrated circuit 23 is alsoconnected to each sensor electrode 22 y via the corresponding one of thesecond lead-out wires 24 y. The second lead-out wires 24 y are arrangedso as to correspond one-to-one to the sensor electrodes 22 y.

The first integrated circuit 13 has a function of detecting the stylus Pand the finger F present on the first panel surface 11, a function ofderiving the position of the detected stylus P or finger F within thefirst panel surface 11 and supplying position data indicating thederived position to the host processor 30, and a function ofbidirectionally transmitting and receiving signals to and from thestylus P via the first sensor electrode groups 12 x and 12 y. Similarly,the second integrated circuit 23 has a function of detecting the stylusP and the finger F present on the second panel surface 21, a function ofderiving the position of the detected stylus P or finger F within thesecond panel surface 11 and supplying position data indicating thederived position to the host processor 30, and a function ofbidirectionally transmitting and receiving signals to and from thestylus P via the second sensor electrode groups 22 x and 22 y. The firstintegrated circuit 13 and the second integrated circuit 23 areconfigured to execute these functions in synchronization with eachother, either under the control of the host processor 30 or bycommunicating with each other via the wire 31.

In the following description, a signal transmitted from the firstintegrated circuit 13 to the stylus P will be referred to as a firstuplink signal US1, and a signal transmitted from the second integratedcircuit 23 to the stylus P will be referred to as a second uplink signalUS2. It is noted that, when the first uplink signal US1 and the seconduplink signal US2 do not need to be distinguished from each other, thefirst uplink signal US1 and the second uplink signal US2 may becollectively referred to as an uplink signal US. Further, a signaltransmitted from the stylus P will be referred to as a downlink signalDS.

A region US1 a illustrated in FIG. 1 is a range that the first uplinksignal US1 can reach. Further, a region US2 a illustrated in FIG. 1 is arange that the second uplink signal US2 can reach. As is clear from thedescription of FIG. 1 , the region US1 a and the region US2 a overlapwith each other depending on the angle formed between the first housing10 and the second housing 20. The stylus P present within thisoverlapping region can receive both the first uplink signal US1 and thesecond uplink signal US2. Therefore, it is necessary to preventinterference between the first uplink signal US1 and the second uplinksignal US2 in the electronic device 1.

Referring back to FIG. 2 , the host processor 30 is a central processingunit of the electronic device 1 that executes an operating system andvarious applications of the electronic device 1 by reading and executingprograms stored in a memory, which is not illustrated. The hostprocessor 30 also plays a role of accepting pen input by the stylus P ortouch input by the finger F via the first integrated circuit 13 and thesecond integrated circuit 23 and supplying the pen input or touch inputto the operating system or an application. Examples of the applicationthat operate in response to receipt of pen input or touch input includea drawing application. This type of application generates and drawsstroke data based on the pen input or touch input.

FIG. 3 is a timing diagram illustrating an overview of operations of thefirst integrated circuit 13 and the second integrated circuit 23. Asillustrated in this figure, the first integrated circuit 13 and thesecond integrated circuit 23 are configured to alternately andrepeatedly perform a pen detection operation PD for detecting the stylusP and a touch detection operation TD for detecting the finger F at thesame timing.

The overview of each of the pen detection operation PD and the touchdetection operation TD will be described below. It is noted that,although the following description takes the first integrated circuit 13as an example, the description similarly applies to the secondintegrated circuit 23.

First, the pen detection operation PD will be described. As illustratedin FIG. 3 , a period in which the pen detection operation PD isperformed includes an uplink signal US transmission/reception period P1and a downlink signal DS transmission/reception period P2. Of these, thedownlink signal DS transmission/reception period P2 is divided into aplurality of time slots TS1 to TSn, enabling a plurality of styluses Pto transmit the downlink signal DS by time division multiplexing.Although not illustrated, another multiplexing method such as frequencydivision multiplexing or orthogonal frequency division multiplexing maybe used in addition to or instead of time division multiplexing. Thefollowing description continues, taking as an example a case where timedivision multiplexing and frequency division multiplexing are used.

The first integrated circuit 13 is configured to periodically transmitthe first uplink signal US1 that includes pairing information by usingthe uplink signal US transmission/reception period P1. The pairinginformation specifies a local pen ID (Identifier), a time slot, and afrequency to be allocated to a newly detected stylus P. When the stylusP that has received this first uplink signal US1 has not been pairedwith any of the integrated circuits, the stylus P transmits the downlinksignal DS that includes a pen ID stored in its memory, by using the timeslot and frequency indicated by the first uplink signal US1. At the sametime, the stylus P stores the pairing information included in the firstuplink signal US1 in its memory.

Here, each time slot included in the transmission/reception period P2 isassigned a number in advance, and the first integrated circuit 13 isconfigured to specify a time slot by specifying the assigned number. Thestylus P is configured to determine a temporal position of each timeslot based on a timing at which the first uplink signal US1 has beenreceived and then transmit the downlink signal DS in the time slotallocated by the pairing information. The example illustrated in FIG. 3is a case where time slots TS2, TS4, and TSn are allocated by thepairing information.

The first integrated circuit 13 that has received the downlink signal DSstores the received pen ID in its memory in association with theabove-described pairing information. Pairing between the firstintegrated circuit 13 and the stylus P is completed through theprocessing up to this point. After that, the first integrated circuit 13transmits the first uplink signal US1 including the local pen ID and acommand as necessary to instruct the paired stylus P what data thestylus P should transmit.

The stylus P is configured to transmit a position signal and a datasignal as the downlink signal DS. The position signal is a burst signal.The data signal is a signal obtained by modulating a predeterminedcarrier signal by using the data indicated (requested) by the firstuplink signal US1. The first integrated circuit 13 derives the positionof the stylus P based on reception strength of the position signal ateach of the sensor electrodes 12 x and 12 y, and obtains the datatransmitted from the stylus P by receiving and demodulating the datasignal. The first integrated circuit 13 then outputs the position dataindicating the derived position and the data obtained from the stylus Pto the host processor 30.

Next, the touch detection operation TD will be described. FIG. 4 is adiagram illustrating a principle of the touch detection operation TD.Although only four sensor electrodes 12 x are illustrated in this figureto simplify illustration, more sensor electrodes 12 x are arranged inactual implementation. The following description continues, assumingthat the number of sensor electrodes 12 x is K.

The first integrated circuit 13 when performing the touch detectionoperation TD supplies a finger touch detection signal FDS to each sensorelectrode 12 x. As illustrated in FIG. 4 , the finger touch detectionsignal FDS includes K signals s₁ to s_(K). Each of the K signals s₁ tos_(K) is made up of K pulses each represented by “1” or “−1,” forexample. The nth pulses (n=1 to K) of the respective signals s₁ to s_(K)constitute a pulse group p_(n). The pluses constituting one pulse groupP_(n) are individually input into the respective sensor electrodes 12 xin parallel.

While the number of sensor electrodes 12 x is assumed to be four (i.e.,K=4) in the following description, the description similarly applies toa case where the number of sensor electrodes 12 x is three or less orfive or more. When the number of sensor electrodes 12 x is four, each ofthe signals s₁ to s_(K) is made up of four pulses each represented by“1” or “−1.” Specifically, as illustrated in FIG. 4 , the signal s₁ ismade up of “1, 1, 1, 1,” the signal s₂ is made up of “1, 1, −1, −1,” thesignal s₃ is made up of “1, −1, −1, 1,” and the signal s₄ is made up of“1−1, 1, −1.”

The first integrated circuit 13 includes a shift register 13 a and acorrelator 13 b. The shift register 13 a is a FIFO (First-InFirst-Out)-type storage unit and is configured to store the same number(i.e., K) of pieces of data as the number of sensor electrodes 12 x.When new data is stored in the shift register 13 a, the data that hasbeen stored K times prior is deleted from the shift register 13 a. Thefirst integrated circuit 13 selects one sensor electrode 12 y andsequentially inputs the pulse groups p₁ to p₄ to each sensor electrode12 x. The first integrated circuit 13 repeats this operation for eachsensor electrode 12 y. Accordingly, four levels L₁ to L₄ correspondingto the respective pulse groups p₁ to p₄ sequentially appear in theselected sensor electrode 12 y. The first integrated circuit 13sequentially obtains the levels L₁ to L₄ appearing in the sensorelectrode 12 y in this way, and each time the first integrated circuit13 obtains the level, the first integrated circuit 13 stores theobtained level in the shift register 13 a.

The specific contents of the levels L₁ to L₄ will be described indetail, taking as an example a case where a sensor electrode 12 y ₁illustrated in FIG. 4 is selected. In the following description,capacitances formed between the sensor electrode 12 y ₁ and four sensorelectrodes 12 x ₁ to 12 x ₄ will be referred to as C₁₁ to C₄₁,respectively.

First, the level L₁ corresponding to the pulse group p₁ and stored inthe shift register 13 a is an inner product of a capacitance vector(C₁₁, C₂₁, C₃₁, C₄₁) and a vector (1, 1, 1, 1) indicating the pulsegroup p₁. This inner product is calculated as C₁₁+C₂₁+C₃₁+C₄₁ as alsoillustrated in FIG. 4 . Similarly, the level L₂ corresponding to thepulse group p₂ and stored in the shift register 13 a is an inner productof the capacitance vector (C₁₁, C₂₁, C₃₁, C₄₁) and a vector (1, 1, −1,−1) indicating the pulse group p₁, which is calculated asC₁₁+C₂₁−C₃₁−C₄₁. The level L₃ corresponding to the pulse group p₃ andstored in the shift register 13 a is an inner product of the capacitancevector (C₁₁, C₂₁, C₃₁, C₄₁) and a vector (1, −1, −1, 1) indicating thepulse group p₃, which is calculated as C₁₁−C₂₁−C₃₁+C₄₁. The level L₄corresponding to the pulse group p₄ and stored in the shift register 13a is an inner product of the capacitance vector (C₁₁, C₂₁, C₃₁, C₄₁) anda vector (1, −1, 1, −1) indicating the pulse group p₄, which iscalculated as C₁₁−C₂₁+C₃₁−C₄₁.

The first integrated circuit 13 uses the correlator 13 b to sequentiallycalculate correlation values T₁ to T₄ correlating with the levels L₁ toL₄ accumulated in the shift register 13 a for the respective four pulsegroups p₁ to p₄. As illustrated in FIG. 4 , the specific contents of thecorrelation values T₁ to T₄ calculated in this way are 4C₁₁, 4C₂₁, 4C₃₁,and 4C₄₁, respectively. That is, the correlation values T₁ to T₄ eachreflect changes in capacitances formed at intersections of the sensorelectrodes 12 x ₁ to 12 x ₄ and the sensor electrode 12 y ₁. Therefore,the first integrated circuit 13 can detect the position of the finger Fby referring to the correlation values T₁ to T₄ calculated for eachsensor electrode 12 y. Specifically, it suffices that the firstintegrated circuit 13 determines a region within the first panel surface11 where changes in capacitances are equal to or greater than apredetermined value and detects the center position of the region as theposition of the finger F, for example. The first integrated circuit 13is configured to also output the position data indicating the positiondetected in this way to the host processor 30.

FIGS. 5A and 5B are diagrams each illustrating an example of specificwaveforms of the signals s₁ to s_(K) that constitute the finger touchdetection signal FDS. The signals s₁ to s_(K) according to a firstexample illustrated in FIG. 5A include signals representing “1” by arelatively high voltage and “−1” by a relatively low voltage. Meanwhile,the signals s₁ to s_(K) according to a second example illustrated inFIG. 5B include signals obtained by Manchester-encoding the signals s₁to s_(K) according to the first example. Specifically, each signalrepresenting a signal value consists of a first half portion, whichrepresents “1” or “−1” depending on a high or low voltage, and a latterhalf portion, which represents the intermediate voltage. In thefollowing description, a section in which the value of “1” or “−1” isreflected in the voltage may be occasionally referred to as a singlepulse section PS, as illustrated in FIGS. 5A and 5B.

Next, a configuration of the sensor system 3 that relates to thecharacteristics of the present disclosure will be described in detailwith reference to FIGS. 6 to 8 .

FIG. 6 is a timing diagram of signals transmitted and received by eachof the first integrated circuit 13, the second integrated circuit 23,and the stylus P. Illustrated in this figure is a state in which thefirst integrated circuit 13 and the stylus P have already been paired.

As illustrated in FIG. 6 , the sensor system 3 according to the presentembodiment controls the first integrated circuit 13 and the secondintegrated circuit 23 such that the first uplink signal US1, which istransmitted from the first integrated circuit 13 via the first sensorelectrode groups 12 x and 12 y, and the second uplink signal US2, whichis transmitted from the second integrated circuit 23 via the secondsensor electrode groups 22 x and 22 y, are not transmitted at the sametime. Specifically, the host processor 30 may control the firstintegrated circuit 13 and the second integrated circuit 23 such that thefirst uplink signal US1 and the second uplink signal US2 are nottransmitted at the same time, or the first integrated circuit 13 and thesecond integrated circuit 23 may communicate with each other so as tocontrol the first integrated circuit 13 and the second integratedcircuit 23 such that the first uplink signal US1 and the second uplinksignal US2 are not transmitted at the same time.

As a result of such processing, in the example illustrated in FIG. 6 ,the first uplink signal US1 is transmitted within a period of a timelength T1 from the beginning of the period in which the pen detectionoperation PD is performed, whereas the second uplink signal US2 istransmitted after a time length T2 (>T1), which is longer than the timelength T1, has elapsed since the beginning of the pen detectionoperation PD. As a result, the first uplink signal US1 and the seconduplink signal US2 are not transmitted at the same time. Accordingly, itis possible to prevent interference between the uplink signal UStransmitted from the first panel surface 11 and the uplink signal UStransmitted from the second panel surface 21.

In addition, the first integrated circuit 13 further controls the pairedstylus P such that the paired stylus P does not perform a receivingoperation (denoted as “R” in FIG. 6 ) except for a period in which thefirst uplink signal US1 is being transmitted. Specifically, at the timeof pairing, the first integrated circuit 13 notifies the stylus P of atime length INT illustrated in FIG. 6 . The time length INT representsan interval between transmissions of the uplink signal US. Afterreceiving the uplink signal US, the stylus P operates so as to stop thereceiving operation during the notified time length INT. Accordingly, itis possible to prevent the stylus P paired with the first integratedcircuit 13 from receiving the uplink signal US transmitted from thesecond integrated circuit 23.

Although this description similarly applies to the second integratedcircuit 23, it is preferable that, at the time of pairing, the secondintegrated circuit 23 further notify the stylus P of a time length T3 (atime length from the end of transmission of the second uplink signal US2to the start of the touch detection operation TD) and a time length T4(a time length of a period in which the touch detection operation TD isperformed) illustrated in FIG. 6 . In this way, based on the timing atwhich the second uplink signal US2 has been received, the stylus P candetermine the temporal position of each time slot for transmitting thedownlink signal DS while excluding the period in which the touchdetection operation TD is performed.

Further, the first integrated circuit 13 and the second integratedcircuit 23 are configured such that, when one of the first integratedcircuit 13 and the second integrated circuit 23 is paired with thestylus P, the pairing information regarding the pairing is shared withthe other one of the first integrated circuit 13 and the secondintegrated circuit 23. In sharing the pairing information, one of thefirst integrated circuit 13 and the second integrated circuit 23 maytransmit the pairing information to the host processor 30 and the hostprocessor 30 may transmit this pairing information to the other one ofthe first integrated circuit 13 and the second integrated circuit 23, orone of the first integrated circuit 13 and the second integrated circuit23 may directly transmit the pairing information to the other one of thefirst integrated circuit 13 and the second integrated circuit 23. Thiseliminates the need for performing pairing again when the stylus P movesbetween the first panel surface 11 and the second panel surface 21,thereby enabling continuous use of the stylus P across the first panelsurface 11 and the second panel surface 21.

Further, while one of the first integrated circuit 13 and the secondintegrated circuit 23 is performing the touch detection operation TD,the sensor system 3 according to the present embodiment restricts theother one of the first integrated circuit 13 and the second integratedcircuit 23 from performing the touch detection operation TD. This pointwill be described in detail below with reference to FIG. 7 .

FIG. 7 is a diagram illustrating a state in which the user is slidingthe finger F on the first panel surface 11 with a hand H resting on thesecond panel surface 21. In response to the user performing thisoperation, capacitive coupling occurs not only between the sensorelectrodes 12 x and 12 y and the hand H in a region A1 (a region incontact with the finger F) within the first panel surface 11 illustratedin FIG. 7 , but also between the sensor electrodes 22 x and 22 y and thehand H in a region A2 (a region in contact with the palm) within thesecond panel surface 21 illustrated in FIG. 7 . As a result, the fingertouch detection signal FDS that is being transmitted from the secondintegrated circuit 23 is received by the first integrated circuit 13through a path B illustrated in FIG. 7 . Such reception needs to beavoided because this causes malfunction of the first integrated circuit13 and the host processor 30.

Accordingly, while one of the first integrated circuit 13 and the secondintegrated circuit 23 is performing the touch detection operation TD,the sensor system 3 according to the present embodiment restricts theother one of the first integrated circuit 13 and the second integratedcircuit 23 from performing the touch detection operation TD. Therestriction may be performed such that, while the coordinates of thefinger F are being supplied from one of the first integrated circuit 13and the second integrated circuit 23, the host processor 30 restrictsthe other one of the first integrated circuit 13 and the secondintegrated circuit 23 from performing the touch detection operation TD,or one of the first integrated circuit 13 and the second integratedcircuit 23 that is detecting the finger F notifies the other circuitthat the finger F is being detected. Accordingly, it is possible toprevent the finger touch detection signal FDS that is being transmittedfrom one of the first integrated circuit 13 and the second integratedcircuit 23 from being received by the other one of the first integratedcircuit 13 and the second integrated circuit 23.

It is noted that the first integrated circuit 13 and the secondintegrated circuit 23 or the host processor 30 preferably detects thearea of each region where the touch is detected (the regions A1 and A2illustrated in FIG. 7 ) and selects the integrated circuit to berestricted (prevented) from performing the touch detection operation TDbased on the detected areas. In general, the area detected by thecontact of a fingertip is smaller than the area detected by the contactof the palm and, thus, it is possible to select the integrated circuitin this way to prioritize touch input by the finger F.

Further, in restricting the touch detection operation TD, in onespecific example, it suffices that the touch detection operation TD bythe selected integrated circuit is completely stopped. Further, inanother example, it suffices that, when the selected integrated circuitis the second integrated circuit 23, for example, the second integratedcircuit 23 is controlled so as to perform the touch detection operationTD without using part of the sensor electrodes 22 x (the sensorelectrodes 22 x in a region C illustrated in FIG. 7 ) close to the firstsensor electrode groups 12 x and 12 y.

FIG. 8 is a diagram illustrating yet another example of the restrictionof the touch detection operation TD. In this example, the secondintegrated circuit 23 does not perform the touch detection operation TDwhile the first integrated circuit 13 is performing the touch detectionoperation TD, and the first integrated circuit 13 does not perform thetouch detection operation TD while the second integrated circuit 23 isperforming the touch detection operation TD. To implement thisoperation, it is preferable that one of the first integrated circuit 13and the second integrated circuit 23 notify the other one of the firstintegrated circuit 13 and the second integrated circuit 23 of the starttiming and the end timing of the touch detection operation TD, eitherdirectly or via the host processor 30.

As described above, with the sensor system 3 according to the presentembodiment, the first uplink signal US1 and the second uplink signal US2are not transmitted at the same time. Therefore, it is possible toprevent interference between the uplink signal US transmitted from thefirst panel surface 11 and the uplink signal US transmitted from thesecond panel surface 21.

Further, with the sensor system 3 according to the present embodiment,the pairing information is shared between the first integrated circuit13 and the second integrated circuit 23. This enables continuous use ofthe stylus P across the first panel surface 11 and the second panelsurface 21.

Further, with the sensor system 3 according to the present embodiment,while one of the first integrated circuit 13 and the second integratedcircuit 23 is performing the touch detection operation TD, the other oneof the first integrated circuit 13 and the second integrated circuit 23is restricted from performing the touch detection operation TD.Therefore, it is possible to prevent the finger touch detection signalFDS that is being transmitted from one of the first integrated circuit13 and the second integrated circuit 23 from being received by the otherone of the first integrated circuit 13 and the second integrated circuit23.

Moreover, with the sensor system 3 according to the present embodiment,the first integrated circuit 13 and the second integrated circuit 23each perform the touch detection operation TD in synchronization witheach other. Therefore, the host processor 30 can correctly process thesequence of the position data of the finger F supplied from each of thefirst integrated circuit 13 and the second integrated circuit 23.

Next, a second embodiment of the present disclosure will be described.The present embodiment is different from the first embodiment in thesolution to the problem described with reference to FIG. 7 and issimilar to the first embodiment in other respects. Therefore, thefollowing description continues, focusing on the difference from thefirst embodiment.

FIGS. 9A and 9B are diagrams each illustrating waveforms of the fingertouch detection signal FDS according to the present embodiment. FIG. 9Aillustrates the case where the finger touch detection signal FDS is madeup of the signals with the waveforms illustrated in FIG. 5A. FIG. 9Billustrates the case where the finger touch detection signal FDS is madeup of the signals with the waveforms illustrated in FIG. 5B.

The first integrated circuit 13 and the second integrated circuit 23 areeach configured to receive the finger touch detection signal FDS bydetecting a change in the signal at the edge (leading edge) of eachpulse section PS. Therefore, in the present embodiment, the finger touchdetection signal FDS supplied from the first integrated circuit 13 toeach sensor electrode 12 x (hereinafter referred to as a first fingertouch detection signal FDS) and the finger touch detection signal FDSsupplied from the second integrated circuit 23 to each sensor electrode22 x (hereinafter referred to as a second finger touch detection signalFDS) are each configured such that the temporal positions of the edgesof their respective pulse sections PS are different from each otherbetween the first finger touch detection signal FDS and the secondfinger touch detection signal FDS.

In a typical example, it suffices that the first finger touch detectionsignal FDS and the second finger touch detection signal FDS are made upof pulse signals having different phases from each other. For example,as illustrated in FIGS. 9A and 9B, it suffices that the first fingertouch detection signal FDS and the second finger touch detection signalFDS are configured such that their respective phases are different fromeach other by a time PS/2 that is one half of the above-described singlepulse section PS. Accordingly, the temporal positions of the edges ofthe pulse sections PS (timings denoted by black triangles in FIGS. 9Aand 9B) can be different from each other between the first finger touchdetection signal FDS and the second finger touch detection signal FDS.

In this way, the first finger touch detection signal FDS and the secondfinger touch detection signal FDS are configured such that the temporalpositions of the edges of their respective pulse sections PS aredifferent from each other between the first finger touch detectionsignal FDS and the second finger touch detection signal FDS.Accordingly, at a timing when one of the first integrated circuit 13 andthe second integrated circuit 23 performs the operation of detecting asignal change, a signal corresponding to the other circuit alwaysremains unchanged. Therefore, it is possible to prevent the finger touchdetection signal FDS that is being transmitted from one of the firstintegrated circuit 13 and the second integrated circuit 23 from beingreceived by the other one of the first integrated circuit 13 and thesecond integrated circuit 23.

It is noted that, instead of the phases of the first finger touchdetection signal FDS and the second finger touch detection signal FDS,their frequencies (i.e., the time length of the pulse section PS) may bedifferent from each other. In this way, the temporal positions of theedges of the pulse sections PS can also be substantially, though notcompletely, (that is, at most of the timings) different from each otherbetween the first finger touch detection signal FDS and the secondfinger touch detection signal FDS.

Further, in addition to each configuring the first finger touchdetection signal FDS and the second finger touch detection signal FDSsuch that their respective rising and falling time lengths are differentfrom each other between the first finger touch detection signal FDS andthe second finger touch detection signal FDS, the first integratedcircuit 13 and the second integrated circuit 23 may be each configuredto receive only the finger touch detection signal FDS of a specificfrequency by using a band-pass filter that passes only a signal of thespecific frequency, for example. In this way, it is also possible toprevent the finger touch detection signal FDS that is being transmittedfrom one of the first integrated circuit 13 and the second integratedcircuit 23 from being received by the other one of the first integratedcircuit 13 and the second integrated circuit 23.

Further, if an increase in bit lengths of the above-described signals s₁to s_(K) is acceptable, all of the signals s₁ to s_(K) transmitted fromthe first integrated circuit 13 and the signals s₁ to s_(K) transmittedfrom the second integrated circuit 23 may be made up of code stringsorthogonal to each other. In this way, each of the first integratedcircuit 13 and the second integrated circuit 23 can receive each signalin a distinguished manner by calculating correlation with the orthogonalcode strings stored in advance. Accordingly, similarly to thedescription above, it is possible to prevent the finger touch detectionsignal FDS that is being transmitted from one of the first integratedcircuit 13 and the second integrated circuit 23 from being received bythe other one of the first integrated circuit 13 and the secondintegrated circuit 23.

Although the preferred embodiments of the present disclosure have beendescribed above, the present disclosure is by no means limited to theabove-described embodiments. As a matter of course, the presentdisclosure can be implemented in various modes without departing fromthe scope of the present disclosure.

For example, the first integrated circuit 13 and the second integratedcircuit 23 may transmit their respective uplink signals US with the samecontent at the same timing. In other words, the first integrated circuit13 and the second integrated circuit 23 may be integrally operated. Inthis way, it is also possible to prevent interference between the uplinksignal US transmitted from the first panel surface 11 and the uplinksignal US transmitted from the second panel surface 21. In this case aswell, as to the touch detection operation TD, it is preferable to ensurethat, in the way described above, the finger touch detection signal FDSthat is being transmitted from one of the first integrated circuit 13and the second integrated circuit 23 is not received by the other one ofthe first integrated circuit 13 and the second integrated circuit 23.

It is noted that, when both the first panel surface 11 and the secondpanel surface 21 are configured by touch displays employing the in-cellsystem described above and the first integrated circuit 13 and thesecond integrated circuit 23 transmit their respective uplink signals USwith the same content at the same timing as described above, it ispreferable to synchronize vertical synchronization signals VSyncindicating a screen rewriting timing. That is, with the touch displaysemploying the in-cell system, the sensor system 3 can perform the pendetection operation PD and the touch detection operation TD only duringa blank period in which a pixel driving operation is not performed.Therefore, in order for the first panel surface 11 and the second panelsurface 21 to transmit their respective uplink signals US at the sametiming, the temporal positions of the blank periods need to matchbetween the first panel surface 11 and the second panel surface 21. Bysynchronizing the vertical synchronization signals VSync with each otheras described above, the temporal positions of the blank periods canmatch.

Further, the first uplink signal US1 and the second uplink signal US2may be made up of signals modulated by using code strings orthogonal toeach other. In this way, the stylus P can receive the first uplinksignal US1 and the second uplink signal US2 in a distinguished manner bycalculating the correlation with the orthogonal code strings stored inadvance. Therefore, similarly to the description above, it is possibleto prevent interference between the uplink signal US transmitted fromthe first panel surface 11 and the uplink signal US transmitted from thesecond panel surface 21. It is noted that, when, in this case, thestylus P receives both the first uplink signal US1 and the second uplinksignal US2, it is preferable that the stylus P select one of the firstuplink signal US1 and the second uplink signal US2 and perform pairingwith the integrated circuit that corresponds to the selected one. Forexample, it suffices that the stylus P selects one of the first uplinksignal US1 and the second uplink signal US2 that exhibits a greaterreception strength.

DESCRIPTION OF REFERENCE SYMBOLS

-   -   1: Electronic device    -   2: Connecting portion    -   3: Sensor system    -   10: First housing    -   11: First panel surface    -   12 x, 12 y: First sensor electrode group    -   13: First integrated circuit    -   13 a: Shift register    -   13 b: Correlator    -   14 x, 14 y: First lead-out wire    -   20: Second housing    -   21: Second panel surface    -   22 x, 22 y: Second sensor electrode group    -   23: Second integrated circuit    -   24 x, 24 y: Second lead-out wire    -   30: Host processor    -   31 to 33: Wire (Line/Trace)    -   A1: A region in contact with a finger F    -   A2: A region in contact with a palm    -   DS: Downlink signal    -   F: Finger    -   FDS: Finger touch detection signal    -   H: Hand    -   INT: A time length of an interval for transmitting an uplink        signal US    -   P: Stylus    -   P1: Uplink signal US transmission/reception period    -   P2: Downlink signal DS transmission/reception period    -   p₁ to p₄: Pulse group    -   PD: Pen detection operation    -   PS: Pulse section    -   s₁ to s_(K): Signal    -   T1: A time length of a period in which a first uplink signal US1        is transmitted    -   T₁ to T₄: Correlation value    -   T2: A time length from the beginning of the pen detection        operation PD to the start of transmission of a second uplink        signal US2    -   T3: A time length from the end of transmission of the second        uplink signal US2 to the start of a touch detection operation TD    -   T4: A time length of a period in which the touch detection        operation TD is performed    -   TD: Touch detection operation    -   TS1 to TSn: Time slot    -   US: Uplink signal    -   US1: First uplink signal    -   US1 a: A range that the first uplink signal US1 can reach    -   US2: Second uplink signal    -   US2 a: A range that the second uplink signal US2 can reach

The invention claimed is:
 1. A sensor system comprising: a first sensorelectrode group and a first integrated circuit connected to the firstsensor electrode group; and a second sensor electrode group and a secondintegrated circuit different from the first integrated circuit andconnected to the second sensor electrode group, wherein the first sensorelectrode group is disposed under a first panel surface and the secondsensor electrode group is disposed under a second panel surfacedifferent from the first panel surface, and the first panel surface isrotatable with respect to the second panel surface, wherein, when thefirst integrated circuit is paired with a stylus, the first integratedcircuit shares pairing information regarding the pairing, with thesecond integrated circuit, wherein a reach of a first uplink signaltransmitted from the first integrated circuit via the first sensorelectrode group overlaps with a reach of a second uplink signaltransmitted from the second integrated circuit via the second sensorelectrode, responsive to the first panel surface, from which the firstuplink signal is transmitted, being rotated to assume an angle less than180 degrees relative to the second panel surface, from which the seconduplink signal is transmitted, and wherein the first and secondintegrated circuits are controlled such that the first uplink signal istransmitted from the first panel surface at a first timing and thesecond uplink signal is transmitted from the second panel surface at asecond timing which alternates with the first timing.
 2. The sensorsystem according to claim 1, wherein the pairing information isinformation that specifies each of a local pen identifier, a time slot,and a frequency that are allocated to the stylus by the first integratedcircuit.
 3. The sensor system according to claim 1, further comprising:a host processor connected to the first and second integrated circuits,wherein, in sharing the pairing information between the first and secondintegrated circuits, the first integrated circuit transmits the pairinginformation to the host processor and the host processor transmits thepairing information to the second integrated circuit.
 4. The sensorsystem according to claim 1, wherein, in sharing the pairing informationbetween the first and second integrated circuits, the first integratedcircuit transmits the pairing information to the second integratedcircuit.
 5. The sensor system according to claim 1, further comprising:a first housing including a first panel surface; and a second housingincluding a second panel surface, wherein the first integrated circuitis disposed in the first housing, and the second integrated circuit isdisposed in the second housing.
 6. The sensor system according to claim5, wherein the first housing is rotatable with respect to the secondhousing.
 7. The sensor system according to claim 5, wherein the firsthousing is connected to the second housing by a connecting portion, andthe connecting portion includes a hinge.